Neurostimulation, also referred to as neuromodulation, has been proposed as a therapy for a number of conditions. Examples of neurostimulation include Spinal Cord Stimulation (SCS), Deep Brain Stimulation (DBS), Peripheral Nerve Stimulation (PNS), and Functional Electrical Stimulation (FES). Implantable neurostimulation systems have been applied to deliver such a therapy. An implantable neurostimulation system may include an implantable neurostimulator, also referred to as an implantable pulse generator (IPG), and one or more implantable leads each including one or more electrodes. The implantable neurostimulator delivers neurostimulation energy through one or more electrodes placed on or near a target site in the nervous system. An external programming device is used to program the implantable neurostimulator with stimulation parameters controlling the delivery of the neurostimulation energy.
In one example, the neurostimulation energy is delivered in the form of electrical neurostimulation pulses. The delivery is controlled using stimulation parameters that specify spatial (where to stimulate), temporal (when to stimulate), and informational (signals directing the nervous system to respond as desired) aspects of a pattern of neurostimulation pulses. The human nervous systems use neural signals having sophisticated shapes and patterns to communicate various types of information, including sensations of pain, pressure, temperature, etc. It may interpret an artificial stimulation with a simple pattern of stimuli as an unnatural phenomenon, and respond with an unintended and undesirable sensation, response, and/or movement. Also, as the condition of the patient may change while receiving a neurostimulation therapy, the characteristic of the neurostmulation energy applied to the patient may need to be changed to maintain efficacy of the therapy while minimizing the unintended and/or undesirable sensation, response, and/or movement. While modern electronics can accommodate the need for generating sophisticated signals that emulate natural patterns of neural signals observed in the human body, the capability of a neurostimulation system depends on its post-manufacturing programmability to a great extent. For example, a sophisticated pulse pattern may only benefit a patient when it is customized for that patient, with potential interactions between neurostimulation pulses controlled to ensure therapy efficacy and safety. This makes programming of a stimulation device for a patient a challenging task.